THE EFFECT OF INFLAMMATION ON BLOOD-VESSEL AREA IN ROSENTHALS CANAL IN THE CAT COCHLEA

The quantitative analysis of spiral ganglion cells is important. It is conventionally expressed as a cell density, the number of cells withi n Rosenthal's canal divided by its area. The area of Rosenthal's canal conventionally excludes the areas of blood vessels within it. If bloo d vessels proliferate in an inflammatory response then excluding their area may result in an under-estimate of cell loss. This study investi gates whether blood vessel area increases with inflammation. Eighteen implanted and stimulated cat cochleas were studied. Using computer aid ed analysis techniques we measured the areas of Rosenthal's canals and its blood vessels. A histologist quantitatively graded the inflammati on in each cochlea. Blood vessel area increased with the grade of infl ammation. Multiple regression analysis showed this effect was signific ant (P < 0.01). This increase in blood vessel area may have an effect on density measurements made by excluding that area, leading to an und er-estimate of ganglion cell loss.